表示应用程序连接到mongo db的正确方法？

Question

我有一个包含的Node.js/Express应用程序下面的目录布局：

server.coffee 
server.js 
src 
├── config 
│   └── index.coffee 
├── controllers 
│   ├── index.coffee 
│   └── user.coffee 
├── index.coffee 
├── models 
│   └── user 
│    └── user.coffee 
├── routes.coffee 
└── utils 
    ├── dbconnect.coffee 
views 
├── 404.blade 
├── 500.blade 
├── index.blade 
└── user 
    ├── create.blade 

的/src/config/index.coffee有蒙戈URL这是细节我再导出为DB_URL

#### Config file 
# Sets application config parameters depending on `env` name 

logger = require "../utils/logger" 
logCategory = "Server config" 

DB_HOST = "localhost" 
DB_PORT = "27017" 
DB_NAME = "zmgc" 
DB_URL = null 
DB_USER = null 
DB_PASS = null 


# Connecting to dexies database on mongodb 
boundServices = if process.env.VCAP_SERVICES then JSON.parse(process.env.VCAP_SERVICES) else null 
unless boundServices 
    if DB_USER and DB_PASS 
     DB_URL = "mongodb://#{DB_USER}:#{DB_PASS}@#{DB_HOST}:#{DB_PORT}/#{DB_NAME}" 
    else 
     DB_URL = "mongodb://#{DB_HOST}:#{DB_PORT}/#{DB_NAME}" 
else 
    service_type = "mongodb-1.8" 
    credentials = boundServices["mongodb-1.8"][0]["credentials"] 
    DB_URL = "mongodb://" + credentials["username"] + ":" + credentials["password"] + "@" + credentials["hostname"] + ":" + credentials["port"] + "/" + credentials["db"] 

#Set the current environment to true in the env object 
exports.setEnvironment = (env) -> 
    logger.info "Set app environment: #{env}", logCategory 

    switch(env) 
    when "development" 
     exports.DEBUG_LOG = true 
     exports.DEBUG_WARN = true 
     exports.DEBUG_ERROR = true 
     exports.DEBUG_CLIENT = true 
     exports.DB_URL = DB_URL 

    when "testing" 
     exports.DEBUG_LOG = true 
     exports.DEBUG_WARN = true 
     exports.DEBUG_ERROR = true 
     exports.DEBUG_CLIENT = true 
     exports.DB_URL = DB_URL 

    when "staging" 
     exports.DEBUG_LOG = true 
     exports.DEBUG_WARN = true 
     exports.DEBUG_ERROR = true 
     exports.DEBUG_CLIENT = true 
     exports.DB_URL = DB_URL 

    when "production" 
     exports.DEBUG_LOG = false 
     exports.DEBUG_WARN = false 
     exports.DEBUG_ERROR = true 
     exports.DEBUG_CLIENT = false 
     exports.DB_URL = DB_URL 
    else 
     logger.info "Environment #{env} not found", logCategory 

，然后在/src/utils/dbconnect.coffee，我有以下几点：

# Connecting to database on mongodb 
config = require "../config/index" 
logger = require("./logger") 
mongoose = require("mongoose") 
mongoose.set "debug", true 

logCategory = "DATABASE Connection" 

db_connect_mongo = init: (callback) -> 
    self = this 
    mongo_options = db: 
     safe: true 
    db_url = config.DB_URL 
    mongoose.connect db_url, mongo_options 
    db = self.db_mongo = mongoose.connection 

    db.on "error", (error) -> 
    logger.error "ERROR connecting to: " + db_url, logCategory 
    callback error, null 

    db.on "connected", -> 
    logger.info "SUCCESSFULLY connected to: " + db_url, logCategory 
    callback true, db 

    db.on "disconnected", -> 
    logger.info "DISCONNECTED from the database: " + db_url, logCategory 

# check and connect to Redis 

exports = module.exports = db_connect_mongo 

我在假设正确，一旦我开始申请，/src/index.coffee：

express = require "express" 
logger = require "./utils/logger" 

# Initialize logger 
logger.configure() 

#### Application initialization 
# Create app instance. 
app = express() 

# Define Port 
app.port = process.env.PORT or process.env.VMC_APP_PORT or process.env.VCAP_APP_PORT or 3000 

# Config module exports has `setEnvironment` function that sets app settings depending on environment. 
config = require "./config" 

logCategory = "Server" 

app.configure "development", "testing", "staging", "production", -> 
    config.setEnvironment app.settings.env 

# Database connection 
dbconnection = require "./utils/dbconnect" 
dbconnection.init (result) -> 
    if result 
    logger.info "Database initialized", logCategory 

连接保持打开状态，让我没有继续打开和关闭呢？

这是正确的做法吗？

任何意见非常赞赏。

Answer 1

是的，一旦连接，连接将保持打开状态，直到明确断开或闲置一段时间。从文档：

对于长时间运行的应用程序，通常谨慎启用keepAlive。 没有它，经过一段时间后，您可能会开始看到“连接 已关闭”错误，因为看起来没有理由。如果是这样，阅读 此之后，你可以决定启用保持激活：

你db_connect_mongo违反节点约定，第一个参数是null在成功的情况下调用回调时。要解决此问题，请不要使用callback(true, db)表示成功，请使用callback(null, db)。除此之外，对于那些可以并且应该更简单的事情来说，这有点复杂，你应该有什么工作。